.content {
    position: relative;
    width: 640px;
    height: 640px;
    margin: 100px auto;
}
.btn {
    position: absolute;
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
    background-color: rgba(0,0,0,.3);
    z-index: 2;
}
.btn button {
    position: absolute;
    background: none;
    border: none;
    background-size: 100% 100%;
    cursor: pointer;
    outline: none;
    left: 50%;
    top: 50%;
}
.startBtn button {
    width: 200px;
    height: 80px;
    background-color: skyblue;
    margin-left: -100px;
    margin-top: -40px;
}
.pauseBtn {
    display: none;
}
.pauseBtn button {
    width: 70px;
    height: 70px;
    background-color: tan;
    margin-left: -35px;
    margin-top: -35px;
}

/* snakeWrap */
#snakeWrap {
    position: relative;
    width: 600px;
    height: 600px;
    background-color: #225675;
    border: 20px solid #7dd9ff;
}
/* #snakeWrap div {
    width: 20px;
    height: 20px;
} */
.snakeHead {
    background-color: black;
    /* width: 20px;
    height: 20px; */

}
.snakeBody {
    background-color: gray;
}
.food {
    background-color: red;
}
